what constitutes a word: obviously, a-z... but what about leading, embedded numbers, caps?

what about special characters? I sometimes search program source code, with (), {}, ...

words with embedded string run (eg. fastRun?)

can any of that be enforced to match an adapted search string?

I fully understand that some of these cases maybe outside the scope of X1 - which is perfectly fine. But the technical manual needs be accurate and state what's in and what not ... at the very least, the character set considered forming words must be clear - thanks for any help!